Extrusion of aluminum is done to manufacture various types of components for different purposes. For example, toward the front end of vehicles there is usually provided some shock-absorbing structure. Such structures can include a beam that is intended to collapse (or otherwise deform) upon impact. Extruding the piece can provide desired structural properties, such as strength and low weight. However, if the part has a prismatic shape this can limit the ability of the design to provide a controlled collapse. Similarly, if the part is welded during assembly, the heat-effected zones caused by the welding can also disrupt mechanical properties in unwanted ways.